In the installation and maintenance of electric power cables it is common practice to connect lengths of conductor by inserting ends of the conductors into a tubular metal connector, which is then crimped onto the conductors to connect them together permanently. Because spans of cable are typically quite heavy, the connectors must be strong enough to sustain the high tensile forces, and are therefore necessarily resistant to deformation. It follows that large crimping forces, typically 6 tons or more, are required. The most practical way to produce such large forces is to use hydraulic pressure.
The necessary hydraulic pressure can be generated by a battery powered pump housed along with a battery in the tool itself, by a hand operated pump, or by hydraulic fluid supplied under pressure from a pump separate from the tool.
Similarly large forces are required to operate cutting tools, of which there are various different kinds, some designed for cutting hard wire, and others designed for cutting soft wire.
Cable spearing tools are also operable by hydraulic pressure. In an electric power distribution system, when a particular cable is deenergized for replacement or for maintenance of the cable or electrical equipment fed by the cable, it is important for worker safety to ensure that the cable is not accidentally reenergized. To this end, the cable is grounded by inserting a metal device known as a “spear”, through the sheath of the cable and into contact with the conductor or conductors within the sheath. The spear either connects the internal conductor or conductors to the sheath itself or to another ground point. Spearing tools are similar to crimping and cutting tools.
An electrical utility worker or work crew typically requires several separate hydraulic tools, at least one for crimping, several for cutting, and at least one for spearing. If the workers want to be able to choose from among battery power, hand power and external hydraulic power, a still larger number of separate tools is required.
Although the cutting, crimping and spearing head portions of the tools are different from one another, the hydraulic pumps, pistons and related components can be identical. Nevertheless, tools utilizing a common power unit and interchangeable heads have not been made available. It has also been desirable to make the cutting, crimping, and spearing heads rotatable relative to the hand-held part that contains the pump, the operating piston and related components, so that the tools can be more easily used in manholes and other restricted environments. The desirability of rotation has presented an obstacle to the use of interchangeable heads.